"Regardless of the team, you're just going to go through a stretch like this." -- Brad Ausmus

Detroit Tigers starting pitcher Robbie Ray reacts during the third inning against the Texas Rangers in Detroit on Thursday.AP Photo

DETROIT -- The problem is obvious. Detroit's starters stink as of late. Just look at the numbers.

Prior to the Tigers' three-game series in Cleveland, Detroit's starting pitchers led the majors with a 2.64 ERA and ranked third in the American League with a .224 opponents batting average.

Since then, they've allowed a combined 22 earned runs, which has in turn raised their ERA to 3.19, the fifth-lowest in the majors.

Think about that: Detroit is more than a quarter through its season and its rotation ERA went up half a run in just four days.

"You're going to go through a stretch like this, where maybe you don't get the starting pitching you think you're going to get," Tigers manager Brad Ausmus said. "It ends up taxing the bullpen, and it ends up snowballing for a period of time."

That's certainly been the case for the Tigers, who have been forced to use eight different relievers to eat a combined 18 innings the past four games after Detroit's starters could only last a combined 21 1/3 innings during their four-game skid.

To make matters worse, the Tigers were working with a shorthanded bullpen Thursday as Robbie Ray was brought out of the bullpen to make a spot start in place of Rick Porcello, who had his start pushed back two days due to an injury.

It quickly became a glaring issue as Ray was chased from the game in the fourth inning after the Rangers jumped on the 22-year-old rookie, tagging him for seven runs, all earned, in just 3 1/3 innings.

"Robbie scuffled a little bit," Ausmus said. "He scuffled a little bit with his command, and was coming off the ball. Then, I think he tried to make an adjustment, and started guiding the ball a little bit. He was much sharper in his first two outings."

With Porcello expected to start Saturday, the Tigers were able to bring Drew Smyly out of the bullpen to help absorb some of the punishment. But it was a situation they were hoping to avoid altogether.

"The truth is, the bullpen's taxed," Ausmus said. "You can plan all you want, but the game's going to dictate what gets done."

Ray's early exit proved to be terrible timing for the Tigers, who are in the midst of a 17-game stretch in which they won't get a day off until June 2.

In an effort to add a fresh arm to the bullpen, the Tigers optioned Ray back to Toledo following the game and called up highly touted reliever Corey Knebel from Triple-A Toledo. Knebel will be in uniform Friday and will be available if needed.

"We were actually going to send (Ray) down in Boston, but with the Porcello side injury, we just decided to keep him here for one more start, so we could give Rick an extra couple of days," Ausmus said.

While no one truly expected the starting pitching to continue to match the off-the-chart success from the first quarter of the season, no one could have predicted the team's starting pitching would fall flat in four straight games after recording 14 quality starts in their previous 18 games.

But, like Ausmus said, it happens. Sometimes, there's just no way to explain it.

"I don't want to blame it on the week," Ausmus siad. "Regardless of the team, you're just going to go through a stretch like this."